The present invention relates to mechanical chucks, and more particularly, to a chuck of the expandable type for lifting heavy rolls of paper or other web material upon insertion into the central core thereof.
Large webs of paper, plastic film, or other material used in printing, packaging, etc. are typically wound about central hollow cylindrical fiber or cardboard cores. The rolls may weigh five hundred pounds or more and are stored vertically in warehouses. Mechanisms are required for quickly securing the rolls to an overhead crane, hoist, monorail system or other transport system so that such large rolls can be moved.
Tilt-Lock, Inc. sells a variety of roll and coil lifting devices. They are inserted vertically into the core and have manual or automatic mechanisms that engage teeth with the core. The manual device is engaged with a twist knob. The automatic devices use solenoids and/or suction. At least one of the devices has a gravity activated mechanical lock-up and release mechanism.
Two more commercially available core lifting chucks are the Nim-Cor V.C.L. and the Duo-Grip V.C.L. They each include a pair of stepped, opposing, half-cylinder elongated jaws that are expanded into gripping engagement with the interior of a core by a lever mechanism.
Tilt-Lock, Inc. also sells a spool lifting device for wooden or other larger spools that carry cable, etc. It has a single angled tooth that is manually retracted to allow insertion into the central hole of the spool. The tooth thereafter expands to engage the inside surface of a perpendicularly extending circular side piece of the spool. This device does not appear to be suitable for gripping the inside of a cardboard core.
While the foregoing devices are each functional, I believe that I have invented an improved core lifting chuck which is more compact, less complex and simpler to engage and disengage.